Valve mechanism for hydraulic power presses



April" 17', 1951 B. JAPiKSE VALVE MECHANISM FOR HYDRAULIC POWER PRESSEST3 Sheets-Sheet 1 Filed Janr 25, 1943 April 7, 1951 V 5.. JAP-rKsE: i5 47VAT-NE MECHANISM FUR HYDRAHEIG POWER PRESSE'S Filed Jan." 25, 1943 3Sfiaeis+$heei 2 Patented Apr. 17, 1951 UNITED STATES TENT OFFICE VALVEMECHANISM role HYDRAULIC POWER PRESSES 7 Claims.

' This application is a continuation-in-part of my copending applicationSerial Number 454,168, filed August 8, 1942, for Valve Mechanism, nowabandoned.

The invention relates to a hydraulic power press and more particularlyto a selectively controlled means for controlling the action of amovable platen thereof.

The general object of the invention is to provide operating means whichserves to prevent a lowering action of a movable mechanism before thedriving mechanism has attained a predetermined speed or before theproper controls have become effective, to thereby'prevent a suddenlowering or dropping action or movement of the movable platen while thepress is in operation.

A further object of the invention is to provide 7 control means in ahydraulic power press whereby a movable platen-can be restrained at apredetermined position during its downward travel or movement and inthis manner cause the platen to be lowered at high speed 'prior to theactual initial pressing operation.

Another object of the invention is to provide control means in ahydraulic power press where- 'by'a movable platen remains comparativelyreprovide, in a hydraulic power press, a valve mechanism for positivelycontrolling the flow of fluid pressure from or to pullback cylinders.

Another detailed object of the invention is to provide, in a hydraulicpower press, a valve mechanism so arranged. and constructed that whenthe power or electrical energy is cut off from the press the valvemechanism will be ac-. tuated or' energized to maintain fluid pressurein pullback cylinders to thereby prevent an unwarranted lowering actionor pressing movement of a movable platen. I

The above, as well as numerous other objects,

will become apparent from the succeeding description considered togetherwith the accompanying drawings wherein:

Figure l is a perspective more or less detailed view of a hydraulicpower press embodying the present invention. 7

Figure 1A is a schematic view of the hydraulic power press shown inFigure 1.

Figure 2 is a vertical detailed view, shown partially in section andpartially in elevation, of a valve mechanism forming a part of thepresent invention.

Figure 3 is a partial horizontal view and a par tial plan view takenalong the lines 33 of Figure 2, looking in the direction of the arrows.

Figure 4 is a vertical sectional view taken along the lines 44 of Figure2, looking in the direction of the arrows.

Referring now to the drawings in detail, wherein like numerals refer tolike parts, the reference character A indicates, in a general manner, ahydraulic power press of the present invention. The hydraulic powerpress comprises a lower or stationary platen B having rising therefromsuitable columns C supporting at their up per extremities a top headcylinder casting D. Interposed between the top head cylinder casting andlower platen is a movable platen E arranged, through suitable mechanismhereinafter described, to be moved ina vertical direction toward andaway from the stationary platen and guided through its range of movementby the columns. Mounted on one side of the top head cylinder casting is.a suction tank F forming a container for a source of supply of fluidemployed in the operation of the hydraulic power press. Associated withthe suction tank is an electrical motor G connected through a flexiblecoupling H to a high pressure hydraulic or main pump I With a gear pumpJ built therein. Coming out of the main pump at K is an outlet which isconnected to a main cylinder L through a pipe M to deliver fluid underpressure to the main cylinder and urge an operating ram N out of themain cylinder. The operating ram is joined to or forms a part. of themovable platen so that any action of the operating ram will be reflectedin the movable platen. Part 0 is the stroke control device of the pumpand at location P of the vof breaking pressure, the pipe S serves toreturn the fluid over the main'piston in this valve back to the storagetank. Part T associated with the pilot relief valve is a hydraulicoperated and spring-return pilot three-way valve; When the 4 pressurecontrolling the piston in the pilot relief valve shifts, a pipe line Ufunctions as a drainage line to return fluid back into the surge tank.This oil or fluid will subsequently be returned fromthe surge tank 11."to the suction tank when sufficient excess oil has been discharged intothe surge tank to cause it to over-flow over the bafiie plate U in thesurge tank. The pres-- sure control piston (not shown) is built into themain bod of the pilot relief valve R. At V is indicated generally, amicro switch associated with the pilot relief valve which form a meansor pressure tripping device for reversing the action of the movableplaten.

Forming a part of the hydraulic power press is a valve mechanismgenerally indicated by the reference character i and termed, for. thesake of convenience, a pullback shut-off valve. This valve derives itsfluid pressure through the pipe W connected to a port X of the mainpump. The pullback shut-off valve has, leading in opposite directionstherefrom, conduits Y which convey fluid pressure to adjacent lowerextremities of pullback cylinders Z, the latter of which are spaced oneach side of the press and are suitably anchored in the top headcylinder casting. Each pullback cylinder has a downwardly extendingplunger Z projecting therefrom and which is securel fastened by anysuitable means to the movable platen for the purpose to be hereinafterexplained.

The valve mechanism or pullback shut-off valve'comprises a casing orbody portion 2 preferably of rectangular lormation in horizontal crosssection and having conveniently spaced thereabout on what might beconsidered as a front face 3 thereof, mounting taps for theaccommodation of bolts or any other means (not shown) which retain themechanism is assembled relation with the hydraulic power press. InFigure l of the drawings it will be noted that this valve mechanism isset out in spaced relation from the suction tank. However, thisrelationship has been illustrated merely for the sake of conveniencebecause in actual practice the valve mechanism is anchored to or mountedupon the suction tank or other convenient location. Extending entirelythrough the casing intermediate the height thereof is a circularcross-port or passageway 5 presenting ports 6 at each side face I of thecasing with the ports arranged for the accommodation of any means or anextremity-of the conduits Y which, as previously stated, are connectedat all times to the operating sides of the pullback cylinders. Coaxialwith an axis of the valve mechanism indicated by the diagrammatic line-4 in Figure 2, is a cylindrical chamber 8 extending away from and incommunication with the cross-port or passageway 5. The chamber extendsfrom the limits of the cross-port to the adjacent extremity of thecasing where it merges into a seriesof slightly .enlarged counterbores 9presenting a stepped ararngement or a shoulder ii] facing outwardly ofthe casing. Associated with the one extremity of the casing is a cap orend closing piece H firmly and removably secured to the casing throughthe medium of suitable holding means or bolts 52. The cap is providedwith an outstanding stepped collar l3 formed to be neatly accommodatedby the enlarged cylindrical bores and presenting a shoulder Id disposedoppositely and spaced from the shoulder It. interposed between theshoulders of the casing and the cap is a ring-like gasket i5 of anysuitable material to present a leak-proof seal and prevent the escape offluid from the chamber.

Arranged to move within the chamber in response to fluid pressurederived from a source hereinafter identified is a check valve it havingposition, extends through the passageway for its.

a body portion ll neatly accommodated by the chamber and being providedwith circumambient grooves I8 facing outwardly and radially of the bodyportion for the reception of rings or an nular members [9 bearingagainst the chamber defining wall so as to prevent the escape of fluidfrom the chamber to the passageway and from the passageway to thechamber. The check valve has a reduced portion or neck 20 forming theone extremity thereof and which, in illustrated full length andterminates in an outwardly facing inclined seat 2|. The seat 2| isarranged to selectivel bear against a correspondingly inclined anddisposed seat 22 formed on the casing and defining one limit of thechamber so that when the seat 2! is in contact with the seat 22 asillustrated, fluid may be arrested from escaping from the passageway andhence the conduits Y and pullback cylinders Z; Formed'in one face of thecasing or body is a circular shallowmouth 2'3 having leading therefrom achannel. 24 which communicates with one limit of the chamber in the areaadjacent the inward surface of the cap. Conveniently spaced about themouth but removed therefrom are a plurality of tapped openings (notshown) for the accommodation of mounting bolts to retain a fitting orfixture I) over the mouth. Leading from the fixture o is a pipe 0 whichis in communication with a three-way hydraulic pilot valve (1.Associated with the pilot valve is a solenoid e. By the tripping ofsuitable controls (not shown) the solenoid e may be energized to resultin the pilot valve being operated to permit the, fluid beneath the checkvalve and cap to escape out of the mouth 23 through the pipe 0. andpilot valve to a connecting pipe (2' and enter the suction tank, thusbleeding the fluid from beneath the check valve and cap and permittingthe latter to move toward the cap and thus carry the seat 2! away fromthe seat 22. There is now available at this time a pullback pressureagainst area 6| which develops a pressure equal to this area times thepullback pressure and which, therefore, drives the check valvepositively away from the seat. Leading into or out of the cross-port orpassageway 5 is an-angularly disposed port 25 which, through the mediumof a pipe is in communication with a suitable part of the solenoidoperated three-way hydraulic pilot valve (1 which is so arranged thatwhen the solenoid e is deenergized port 25 is in direct communicationwith the mouth 23 leading to between the check valve and cap. Because ofthis arrangement when the electrical energy fails, which might otherwisecause a sudden drop of the movable platen, port 25 is connected with themouth 23 and the pressure caused 'in the passageway, due to the weightof the movable platen hanging upon the pullback pistons is, through port25, three-way hydraulic pilot valve, mouth '23 and channel 2d, adaptedto act upon the lower exposed area of the check valve lBto urge the seat2! into bearing relation with the seat 22 and thus entrap the fluidpressure within the pullback cylinders. This series of events willprevent an unwarranted downward action or movement of the movable platensince there is a positive forward force driving the check valve 16against the seat 22 and the only opposing force is that of the pullbackpressure acting against the smaller combined areas 6! and 52 andsubsequently only against the still smaller annular area 6! alone ashereinafter explained in more detail. The areas acted upon by thepullback pressure are so proportioned that the differential betweenthese forces is greater than the spring 52, hereinafter referred to inmore detail, and for this reason the check valve is held closed as longas the solenoid e is not energized and this is also the case when themain pump motor is not operating or when certain other controls are notfunctioning as hereinafter described.

So as to prevent an excessive pressure being built up in the pullbackcylinders when the fluid is entrapped therein, there is provided a duct26 angularly disposed to and extending into the casing or body from oneface 21 thereof to the interior of the casing, Where it communicatesdirectly with the passageway. Leading from the duct 26 is a line 9 whichis connected to a relief valve n, the latter being arranged so as to beselectively in communication, through the medium of a line i, with thesuction tank. The relief valve n is installed in the circuit in thefirst instance to function as a safeguard on the pullback system.

That is to say, if for example the solenoid e should fail to operateafter the motor has started and the movable platen is forced downwardlyby the actuation of certain controls designated as 7" to pressingposition, full pressure will be built up over the operating ram and thefull press tonnage will be exerted on the pullback cylinder plungers Z.Accordingly, an abnormal pressure will be therefore built-up in conduitsY which will cause failure of some part of the system at naturally itsweakest part. To prevent damage of any nature resulting from the abovepossible contingency the relief valve n is adjusted to blow off orbecomeactuated when subjected to a 'predesignated pressure value whichis well in excess of the pressure required to raise the movable platenbut however sufliciently low to protect the system against damage incase of the failure of the solenoid e.

To further complete the assembly of fluid connections to the valvecasing there is provided a head 28 removably secured to the casing orbody by means of threaded elements or bolts 29 which extend through thehead and into the casing. In

- alignment with the chamber on an axis of the valve mechanism is a.canal 30 of less diameter than the chamber and extending away from theseat 22 through the casing to terminate in an angularly disposed inlet3| projecting to or through one face 32 of the head where it merges intoa suitable conduit 33. The juncture between the casing and head in theproximity of the canal is of stepped design so as to present opposingshoulders 34 between which there is interposed a suitable packing ring35 of any desired nature. The

stepped arrangement and packing ring forms a leak-proof juncture betweenthe casing and head to prevent the escape of fluid at this location.Port 3| of the pullback shut-off valve is, as previously indicated,connected through the medium of the conduit 63, to a pullback port k onthe pump so that when the pump is delivering fluid into this portpressure will be developed against an exposed end area 62 of the checkvalve iii to urge the check valve seat 2! away from the seat 22 or ifthe check valve is already in the latter named position the fluidpressure will be free to flow from the passageway 39 into the cross-portor passageway 5 and pipes Y to the operating end of the pullbackcylinders for the purpose of rais ing the movable platen. If conditionsare such that the movable platen is being lowered for a pressingoperation then a reverse flow of the fluid will take place between thepullback cylinders and pump through the pullback shut-01f valve. The

; the'small area 52 of the check valve 13 to over come the closing forceand open this valve suffi- V ciently far enough so that the pumpdelivery can be forced into passageway 5 and hence to the pullbackcylinders, thus causing the movable platen to be raised but not loweredso long as the solenoid c has not been energized. When the solenoid e issubsequently energized by the tripping of suitable controls (not shown)the mouth 23 is connected by an action of the three-way valve d to adrain line d which returns any fluid in channel 24 to the suction tank.The line f leading from the port 25 is shut off in the threeway valvewhen this valve has shifted in this manner and the closing force uponthe check valve I6 is-thereby eliminated while the check valve is openedby the action of the hydraulic pressure against the area 6 5. Undercertain conditions the pressure on the pullback cylinders will alwayshold the shutoff valve open which is almost always true during thosepressing operations where the material being pressed yields but verylittle. However, when the material being pressed is veryresilient, thuscausing a long delivery stroke under main cylinder pressure and in suchinstances when the movable platen has contacted the work it is thensupported by the work and the pressure on the pullback cylinders has vanished completely, so much so, that as a matter of fact, the pump may atthat time create a slight suction on the pullback piping. If provisionshereinafter described were not made the arrangement of the pullbackshut-off valve thus far de scribed would lack a definite or positiveforce to prevent the check valve it from seating against or contactingthe seat 22 and experience has taught-that this closing action of thecheck valve actually would take place. After the check valve has seatedand the movable platen has advanced further down during a continuationof a pressing stroke a slight amount of fluid will be expelled out ofthe pullback cylinders'which will cause the check valve to move awayfrom the seat 22 and allow this fluid to escape past the seat 22 intothe canal 30 and when lifting pressure has been released the check valvewill again seat itself thus causing a continual pounding of seat 2|against seat 22 which eventually will cause damage to the seats becauseof this hammeringaction. -To thus eliminate this possible unwarrantedaction it has been found necessary to provide a definite force to holdthe check valve open during this operation of the cycle.

As exemplary of such a definite force there is provided in the pullbackshut-off valve a plunger 35 having a. head 3] thereof interlocked withor positioned in arear of an inwardly directed lip 38 on the reducedportion or neck. Locking the head in position against the lip 38 is aplug or rotatable element 39 extending into and threadedly associatedwith the check valve and having a gasket 40 sealing the juncture betweenthe plug and check valve to prevent the leakage of fluid from the valveto the chamber. Associatijuncture.

'tains the sleeve in a predetermined fixed position. .A packing ring Mis interposed between confronting shoulders 45 on the sleeve and head toprevent the escape of fluid from the canal at this The sleeve of lessdiameter than the accommodating canal is of tubular formation andaccordingly, is provided with an axial bore 46 which extends entirelytherethrough. 'The por tion of sleeve below the packing ring 44 is ofstalk-like formation to form an unbalancing cylinder 4? to be disposedin parallel spaced relation to the wall defining the canal and thusallow the free flow of fluid from the pump to the exposed surface 62 ofthe check valve. In order to maintain the unbalancing cylinder in afixed within the unbalancing cylinder bore to react against an innershoulder 53 in the stalk and the free extremity 54 of the plunger.

If the valve mechanism were merely equipped with the check valve l6 andspring 52, but stem 50, plug as and the unbalancin cylinder were notinstalled, it would be impossible to retain the valve closed by applyingpullback pressure to the port 25, three-way valve d and mouth 23, as theopening force would exceed the closing force by the amount of the springpressure. has, therefore, and for reasons stated on page 8, lines l5 to2!, been found necessary to diminish the force which tends to hold thecheck valve open and this is accomplished by reducing the exposed areaof the check valve by the introduction of the unbalancing cylinder. Aspreviously indicated, the cylinder bore 5! is merely slightly greaterthan the stem 50 so that a rather eiTective seal is obtained whichprevents fluid from leaking profusely out of the canal so between theseparts. There is, however, an extremely slight amount of leakage betweenthe unbalancing cylinder and stem which is carried out through therestricted opening 55 in communication with a line m to the suctiontank. To

prevent hydraulic binding, due to the long area of contact between thesurface of stem 50 and the unbalancing cylinder 4'! a plurality ofcircumambient grooves 57 are formed inthe stem.

When the valve mechanism now describedis opened and it is desired toclose the same by deenergizing the solenoid e the closing force equalsthe entire area of the check valve 16 times the available hydraulicpressure in the pullback system. This, of course, is counteracted by theremaining opening forces which are equal to the full area of the checkvalve is less the area of *the stem or unbalancing cylinder multipliedby the pullback pressure to which of course must be added the value ofthe spring 52. If the cross sectional area of the stem or unbalancincylinder is made sufliciently large that its area times the pullbackpressure is well in excess of the spring pressure it will then beappreciated that there is obtained a definite closing force which willcause the check valve to seat instantly when the electrical energy iscut ofl to deenergize the solenoid e.

Leading'to thecanal 30 through the body portionata position between oneextremity of the 3 bodyand the plane of the passageway is a port 56which is in communication witha surge valve 41' within a surge tank 11through a pipe 0 so that upon a downward action of the movable platenduring a pressing operation some of the fluid enterin the valve willbypass through the port 56 to the surge valve and thereby provide-apilot pressure which will permit a rapid prefllling of the press maincylinder as the movable platen approaches the work.

The press is equipped with a slow-down device p which comprises astandard q secured to and depending a predetermined distance below thetop head cylinder casting. The standard has mounted on the lowerextremity thereof a snap-acting limit switch 1- forming a part of theelectrical circuit of the press. Mounted on the movable platen andarranged to pass and contact the limit switch is a dog .9 so that whenthe movable platen has been lowered to a position where the limit switchis tripped, solenoid e is deenergized and the pullback shut-off valve isclosed immediately, thus making it necessary to pump the movable platendownby building up pressure over the operating ram N and the pressure inthe pullback system is then limited to the setting of the relief valve11..

After the movable platen has been returned to the point where the snapswitch 7 has been reset, solenoid eis again energized and the pullbackshut-on valve acts again in the usual .manner. When operatin thepullback shut-off device in this manner it can thereiorebe used veryadvantageously to not only slow down the movable platen just prior tostriking the work and thereby reduce the impact of contact which in someinstances might be sufficiently severe to cause the material or work onthe stationary platen to jar out of a predetermined position, as well asto prevent impact or subjecting the press to abnormal shocks when thedie breaks through the work during the performance of either a blanking,cupping or drawing operation.

From the above it will be noted that various changes and alterations maybe made to the illustrated and herein described construction withoutdeparting from within the spirit of the invention and scope of theappended claims.

I claim:

1. In a valve mechanism, a body having a crossport extendingtherethrough, a chamber perpendicularly disposed to and communicatingwith said cross-port, a canal in alignment with said chamber andcommunicatin with said cross-port for the admission of fluid thereto, acheck valve in said chamber arranged to arrest the flow of fluid passingfrom said canal to said cross-port upon the introduction of fluidpressure to said chamber against one end of said check valve, andunbalancing means for reducing the exposed area of the other end of saidcheck valve, said unbalancing means comprising a sleeve fixed withrespect to said body and projecting into a recess in said other end ofsaid check valve, and a piston carried by said check valve and receivedin said sleeve.

2. In a valve mechanism, a body having a passageway extending at alltimes uninterrupted therethrough, a chamber perpendicularly disposed toand communicatin with said passageway, a canal in alignment with saidchamber and communicating with said passageway for the introduction offluid to said passageway, a check valve in said chamber arranged'toarrest the flow of fluid from said canal to said passageway upon theintroduction of fluid pressure to said chamber against one end of saidcheck valve, an unbalancing cylinder disposed within said canalcentrally thereof and associated with said check valve to reduce theexposed area of the other end of said check valve, said unbalancingcylinder comprising means extending into said canal in spaced relationthereto, and means outstanding from said last named means formaintaining said unbalancing cylinder in a predetermined position.

3. In a valve mechanism, a body having a passageway extendinguninterrupted therethrough, a chamber perpendicularly disposed to andcommunicating with said passageway, a canal in alignment with saidchamber and communicating with said passageway for the introduction offluid from said canal to said passageway, a check valve in said chamberarranged to arrest the flow of fluid from said canal to said. passagewayupon the introduction of fluid pressure, to said chamber against one endof said check valve, an unbalancing cylinder disposed within said canal,means fixed to and outstanding from said check valve fitting neatlywithin said unbalancing cylinder and resilient means reacting againstsaid unbalancing cylinder and outstanding means.

4. In a valve mechanism, a body having a passageway extendinguninterrupted therethrough and a chamber angularly disposed to andleading from said passageway, a cap closing one end of said chamber, ahead mounted upon said body, a check valve within said chamber arrangedto move therein and selectively arrest the flow of fluid to saidpassageway, a canal within said head and body for the accommodation ofsaid fluid and leading to said passageway in alignment with said checkvalve, a sleeve removably carried by said head and extending into saidcanal, said sleeve having an aperture extending therethroughcommunicating with said canal, a plunger carried by said check valveextending into said aperture, and spring means reacting against saidsleeve and plunger.

5. In a valve mechanism, a body having a passageway extendingtherethrough and a chamber angularly disposed to and leading from saidpassageway, a cover closing one end of said chamber, a head mounted uponsaid body. a check valve within said chamber arranged to move thereinand selectively arrest the flow of fluid in said passageway, a canalwithin said head and body for'the accommodation of said fluid andleading to said passageway in alignment with said check valve, a sleevecarried by said head and extending into said canal, fin means on saidsleeve abutting said body for maintaining said sleeve in fixed positionwithin said canal, and resiliently actuated plunger means carried bysaid check valve and disposed within said sleeve in closely fittedrelation thereto. Y

6. In a valve mechanism, a body having a passageway extending entirelytherethrough and leading in opposite directions, a chamber normal tosaid passageway, a canal in alignment with said chamber andcommunicating with said passageway for the introduction of fluid to saidpassageway, a check valve in said chamber arranged to arrest the flow offluid from said canal to said passageway, a port in said body for theadmission of fluid to said chamber for effecting said check valvearresting action,

means carried by said body extending into said canal and in axialalignment with said check valve, means carried by said check valve andextending into said body carried means, and spring means within saidbody carried means for carried means.

7. In a valve mechanism having a passageway extending through a wallthereof, a chamber angularly disposed relative to said passageway andopen at all times thereto, a canal in alignment with said chamber andcommunicating with said passageway for the introduction of fluid to saidpassageway, a check valve in said chamber arranged to arrest the flow offluid from said canal to said passageway upon the application of fluidpressure against one end of said check valve, and unbalancing means forreducing th exposed area of the other end of said check valve, saidunbalancing means comprising a sleeve fixed with respect to said bodyand extending into said canal in spaced relation thereto, and a pistoncarried by said check valve and slidable in said sleeve.

. BERTRAND JAPIKSE.

REFERENCES CITED The following references are of record in the file ofthis patent: V

UNITED STATES PATENTS Number Name Date 564,167 Thompson July 14, 1896912,022 OBrien Feb. 9, 1909 1,136,211 Collin Apr. 20, 1915 1,777,611Grohek Oct. 7, 1930 2,020,773 Ernst Nov. 12, 1935 2,136,952 Ploen Nov.15, 1938 2,148,543 Dinzl Feb. 28, 1939- 2,227,629 Cannon Jan. 7, 19412,304,634 Ernst Dec. 8, 1942 FOREIGN PATENTS Number Country Date 214,468.Great Britain Apr. 24, 1924 409,391

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